With U.S. President Donald Trump raising previously unthinkable doubts about America’s willingness to defend its traditional NATO allies, some European leaders, officials and military experts insist the Continent must do more to defend itself.

“The EU for decades has profited from the protection the U.S. has provided,” Wolfgang Ischinger, a former German ambassador to Washington who is the chairman of the Munich Security Conference, said in an interview last weekend with the Funke media group. “Today, this protection is not a certainty anymore.”

Proposals for more robust European defense range from a series of Brussels-based initiatives on procurement, training, and research and development, to the extension of France’s nuclear umbrella, to the development of a full-blown EU army, as endorsed recently by French President Emmanuel Macron and German Chancellor Angela Merkel.

Paradoxically, perhaps, the biggest obstacle to the boldest of these proposals might be NATO — the very alliance that has safeguarded the Continent since the end of World War II.

Opposition comes not only from the U.S., which despite Trump’s browbeating of allies to spend more, is intent on preserving a 70-year-old framework that lets Washington call the shots and put its interests first. There’s also pushback from NATO political leaders who are keen to protect their own institutional turf, as well as heavy reluctance from self-doubting Europeans.

“There are some allies who are incentivized, say, to spend more on transportation infrastructure or health services" — Senior NATO diplomat

Proponents of a strong European defense insist the stumbling blocks have more to do with political and financial will than logistics. European diplomats and military experts who have considered the necessity and possibility of a Europe-led collective defense say that the EU’s capabilities are vastly underestimated — including by many Europeans.

Were the EU simply to mass its serving military members it would have the second largest armed force in the world — a total of roughly 1.5 million service members — with only China having more, nearly 2.2 million.

Military experts point to at least one conceivable approach that could deliver relatively quick deterrence against Russia without help from Washington, NATO or the U.K., which is aiming to leave the EU this year.

Rough-sketched, the plan would require massing enough conventional forces in Eastern Europe so as to force Russian President Vladimir Putin, or his successor, to make clear any hostile intentions. And it would require an extension of France’s nuclear capabilities — the so-called force de frappe — to provide a security umbrella over the entire European Continent, with a confirmed large-scale Russian invasion theoretically triggering an immediate strike.

‘Moral hazard’

Yet, as tantalizing as this sort of coordination and capability might be to Europe’s lonely hawks, such talk has barely moved beyond chit-chat in the non-classified “Public Square” space at NATO’s new headquarters in Brussels, where military officials in uniform and diplomats in business suits grab coffee, take money from the ATM, or pick up magazines in the press shop.

And that’s largely because of the alliance itself.

Under the guise of avoiding “duplication” and demanding “complementary” capabilities, the U.S. and NATO’s political leaders continue to put up strong resistance to the EU ever developing the command-and-control capabilities that would allow it to operate outside of the alliance’s existing umbrella.

At NATO, no one wants to be seen discouraging greater EU military investment or cooperation. But the alliance has long served as an excuse for many European governments unwilling to tap tax-payers for often unpopular military spending.

“There is a certain moral hazard in the classic economic sense here,” said a senior NATO diplomat. “There are some allies who are incentivized, say, to spend more on transportation infrastructure or health services.”

When a senior European diplomat at NATO was asked if Europe might be safer — not to mention more in control of its own circumstances — if it were to be able to stand up for itself, the diplomat answered that there is no viable alternative to the existing transatlantic alliance anchored by U.S. supremacy.

German Chancellor Angela Merkel and French President Emmanuel Macron have endorsed a European Army | Michele Tantussi/Getty Images

“It’s not a very good idea; it’s not very realistic,” the diplomat said. “What would we have to put up, to put up a collective European defense? It would require much more than 2 percent [of GDP on military spending]. Parliaments taking decisions to spend 4 percent on defense is just not realistic.”

“The European Union is essentially in a different business than NATO,” the European diplomat said.

Russia worries

The U.S. ambassador to NATO, Kay Bailey Hutchison, has also raised one clear U.S. concern about EU military cooperation: that it not become a cover for protectionism and excluding U.S. defense contractors.

“We do not want this to be a protectionist vehicle for the EU,” Hutchison said at a news conference last year. “We want the Europeans to have capabilities and strength, but not to fence off American products, of course. Or Norwegian products. Or potentially U.K. products.”

Asked on Wednesday in an interview with Deutsche Welle about a new poll showing German and French citizens trust Putin more than Trump, Hutchison was quick to note where Berlin and Paris would seek safety in time of need. “I just think if Germany or France were invaded by a hostile country, they would call America — not Russia,” she said.

But the demand for NATO unity — which Europeans have called for in response to Trump’s criticism of the alliance — also presents something of a trap for the Europeans, who feel pressure not to break publicly with Washington for fear of exposing weakness to rivals like Russia.

This is what made Trump’s withdrawal from the Iran nuclear accord so excruciating for the Europeans. And the unfolding collapse of the Intermediate-Range Nuclear Forces Treaty (INF) offers another clear example.

Although the weapons banned by the treaty pose the greatest direct risk to European countries, a senior Western European diplomat said there wasio chance that the EU’s two nuclear powers — France and Britain — would initiate direct discussions with Moscow on a treaty to protect Europe.

“To have that approach very much plays the game of the Russians,” the senior diplomat said. “My impression is that division would be our greatest weakness.”

“Europe may not be central to the U.S. priorities" — Senior NATO diplomat

At briefings this week ahead of a meeting of NATO defense ministers, European diplomats conceded that the U.S. under President Trump has been extremely unpredictable. Several diplomats expressed relief that Trump had not renewed his attacks on NATO allies over spending during his recent State of the Union speech, and even greater relief that he did not make any threat or suggestion of quitting the alliance.

They also acknowledged serious disagreements with Trump on major policy issues. Trump has insisted, for instance, that ISIS has been defeated, while European countries say it remains a significant threat. In terms of the INF, the U.S. at times has seemed more concerned about being able to deploy weapons to counter threats from China, which was not a party to the INF accord, than about scuttling a treaty that has long protected Europe.

“Europe may not be central to the U.S. priorities,” the senior diplomat admitted.

Brexit factor

At a news conference at NATO headquarters on Tuesday, Secretary-General Jens Stoltenberg insisted that the alliance is not standing in the way of greater EU military integration.

“For me there is no contradiction between EU efforts on defense and a strong NATO,” Stoltenberg said, responding to a question from POLITICO. “Actually, that works perfectly hand in hand, as long as the EU efforts are done in the right way, meaning: not competing, not duplicating with the NATO efforts, but complementing. Then these EU efforts will strengthen the European pillar in NATO.”

Stoltenberg suggested that EU efforts including a project known as Permanent Structured Cooperation (PESCO) and a proposed €13-billion European Defense Fund would provide new capabilities that would only benefit NATO, by filling in gaps. However, he also firmly rejected the notion that the EU could ever — or would ever — be able to defend itself.

“The only thing we have to be focused or aware of is the risk for any duplication or any misperception that this is something that will replace NATO, because, of course, the EU can never replace NATO when it comes to collective defense and protecting Europe,” he said.

Pressed about an EU army, Stoltenberg avoided a direct response, but struck a clearly negative tone.

“What I think is important is that we need to avoid any perception that Europe can manage without NATO, because two World Wars and the Cold War taught us that we need a strong transatlantic bond to preserve peace and stability in Europe,” he said. “Especially after Brexit, it’s obvious that EU efforts cannot replace NATO, because after Brexit, 80 percent of NATO’s defense expenditure will come from non-EU members.”

“The French nuclear capacity should not just cover French territory, but the territory of its European neighbors as well" — Wolfgang Ischinger, chairman of the Munich Security Conference

For some European officials, it’s clear that the idea of going it alone on defense is scarier than remaining beholden to the U.S. despite decisions by Trump that seem to have increased risks for Europe, like pulling out of the Iran nuclear deal, and the befuddling uncertainty that seems to emanate from Washington on a daily basis.

In his recent interview, Ischinger said European allies should pay to help maintain France’s nuclear arsenal in exchange for greater protection. “The French nuclear capacity should not just cover French territory, but the territory of its European neighbors as well,” he said. But for now, he said, NATO is all Europe has got.

“Although most strategic thinkers in Europe agree that a strong transatlantic partnership will remain the best security guarantee for Europe, this preferred option may not be available in the future,” Ischinger warned in a report ahead of this year’s Munich Security Conference, which opens on Friday. “At the same time, a realistic Option B does not exist yet.”